An agricultural seeding machine, such as a row crop planter or grain drill, places the seed at a desired depth within a plurality of parallel seed furrows formed in soil. In the case of a row crop planter, a plurality of row units are typically ground driven using wheels, shafts, sprockets, transfer cases, chains and the like. Each row unit has a frame, which is movably coupled with a tool bar. The frame may carry a main seed hopper, herbicide hopper and insecticide hopper. If the granular herbicide and insecticide are used, the metering mechanisms associated therewith for the dispensing of the granular product into the seed furrow are relatively simple. On the other hand, mechanisms necessary to properly meter seeds at a predetermined rate and to place the seeds at a predetermined relative location and depth within the seed furrow are relatively complicated.
The mechanisms associated with metering and placing of the seeds generally can be divided into a seed metering system and a seed placement system, which are in communication with each other. The seed metering system receives the seeds in a bulk manner from a seed hopper carried by the frame. Different types of seed metering systems can be used such as seed plates, finger plates, seed disks and belts. In the case of a seed disk metering system, a seed disk is formed with a plurality of seed cells spaced about the periphery thereof. Seeds are moved into the seed cells with one or more seeds in each seed cell depending upon the size and configuration of the seed cell. A vacuum or positive pressure airflow may be used in conjunction with the seed disk to assist in movement and retention of the seeds in the seed cells. The seeds are singulated and discharged sequentially at a predetermined rate to the seed placement system.
The seed placement system may be categorized as a gravity drop system or a power drop system. In the case of a gravity drop system, a seed tube has an inlet end, which is positioned below the seed metering system. The singulated seeds from the seed metering system merely drop into the seed tube and fall by way of gravitational force from a discharge end thereof into the seed furrow. The seed tube may be curved in a rearward manner to assist in directing the seed into the seed furrow
A seed placement system of the power drop variety generally can be classified as a seed conveyor belt drop, rotary valve drop, chain drop or air drop. These types of seed placement systems provide somewhat consistent placement of the seeds along a predetermined path at a desired spacing.
Planting of certain crops, such as corn, in what is called “twin-rows” is becoming increasingly popular. With twin-rows, two rows are closely spaced, for example, spaced apart 7.5 inches (19 cm). The centers of the twin rows are spaced 30 inches (76 cm) apart from the next set of twin rows. Within the twin rows, to maximize the yield, it is necessary to alternate the seeds in the twin rows to avoid crowding of the plants. What is needed in the art is an agricultural seeding machine having an automated system to synchronize or to assist the operator in synchronizing the seed placement between rows of seeds.